Substantial effort and attention continues toward the development of newer and more sustainable energy supplies, the conservation of energy by increased energy efficiency remains crucial to the world's energy future. According to an October 2010 report from the U.S. Department of Energy, heating and cooling account for 56% of the energy use in a typical U.S. home, making it the largest energy expense for most homes. Along with improvements in the physical plant associated with home heating and cooling (e.g., improved insulation, higher efficiency furnaces), substantial increases in energy efficiency can be achieved by better control and regulation of home heating and cooling equipment. By activating heating, ventilation, and air conditioning (HVAC) equipment for judiciously selected time intervals and carefully chosen operating levels, substantial energy can be saved while at the same time keeping the living space suitably comfortable for its occupants.
It would be beneficial, at both a societal level and on a per-home basis, for a large number of homes to have their existing older thermostats replaced by newer, microprocessor controlled “intelligent” thermostats having more advanced HVAC control capabilities that can save energy while also keeping the occupants comfortable. In furtherance of this goal, it would be desirable to provide a thermostat whose intelligence is directed not only toward energy savings and human comfort, but whose intelligence is also directed toward making its own installation process as simple and elegant as possible, such that the average do-it-yourselfer, handyman, or other person not having special HVAC system training could undertake the thermostat retrofit process.
In U.S. Pat. No. 5,065,813, which is incorporated by reference herein, an interactive electronic thermostat with installation assistance is discussed. As part of a user-interactive installation testing process discussed therein, the user is required to provide answers to questions presented to them by the system (such as the question, “What turned on?”) about HVAC events that are currently happening. The thermostat discussed in U.S. Pat. No. 5,065,813 believed to bring about one or more disadvantages and/or to contain one or more shortcomings that are addressed and/or avoided by a thermostat provided according to one or more of the embodiments described hereinbelow. Other issues arise as would be apparent to one skilled in the art upon reading the present disclosure.
Provided according to one or more embodiments is a thermostat and related systems, methods, and computer program products for facilitating user-friendly installation thereof. Provided according to one embodiment is a thermostat for controlling the operation of an HVAC system having a plurality of wires requiring connection to the thermostat, each wire being associated with a distinct HVAC signal type. The thermostat comprises a control unit including at least one processor and at least one environmental sensor, and further includes a plurality of connection ports. Each connection port is associated with a predetermined HVAC signal type, and is configured to receive one of the plurality of wires. Associated with each connection port is a wire insertion sensing circuit that identifies to the control unit the presence or absence of an inserted wire therein. The thermostat further comprises a user interface operatively coupled to the control unit, the user interface including at least one output device for providing output information to a user and at least one input device for receiving one or more user inputs. The control unit is configured and programmed to cause the thermostat to carry out an installation verification process. In the installation verification process, the insertion sensing circuits are operated to identify a first subset of the connection ports into which wires have been inserted, the first subset of connection ports having an associated first subset of HVAC signal types. A first candidate HVAC operating function that is consistent with the first subset of HVAC signal types is identified. A first set of control signals is applied to the HVAC system through one or more of the first subset of connection ports, the first set of control signals being configured to instantiate operation of the HVAC system according to the first candidate HVAC operating function. Upon application of the first set of control signals, a first time sequence of environmental readings is acquired using the environmental sensor and processed to automatically determine, without requiring an input from the user, whether the HVAC system has successfully operated according to the first candidate HVAC operating function. An indication of an error condition is provided on the user display if the automatic determination is that the HVAC system has not successfully operated according to the first candidate operating function.
According to another embodiment, the installation verification process carried out by the thermostat further comprises receiving a first input from the user that is indicative of a completion of insertion of the required plurality of wires. Subsequent to receiving the first input, and before applying any set of operating control signals to the HVAC system including the first set of control signals, a second input is received from the user indicative of a user selection to begin normal operation of the HVAC system. Responsive to the received second input and before applying any set of operating control signals to the HVAC system including the first set of control signals, the identification of the first candidate HVAC operating function proceeds in a manner that is consistent with normal operation of the thermostat. More particularly, the first candidate HVAC operating function is assigned as a heating function or a cooling function, but only if the normal operation of the thermostat would call for such heating or cooling function (e.g., the heating function if the current temperature is less than or equal to a heating trip point temperature of the thermostat and the heating function is consistent with the first subset of HVAC signal types, and the cooling function if the current temperature is greater than or equal to a cooling trip point temperature of the thermostat and the cooling function is consistent with the first subset of HVAC signal types). Thus, the first candidate HVAC operating function is not identified, and no operating control signals are applied to the HVAC system, unless and until such operating function would be normally carried out at the currently sensed temperature.
According to another embodiment, an automated determination of a heat pump call convention is performed as part of the installation verification process for cases in which the insertion of an O/B wire was automatically detected as part of the automated wire insertion sensing process. If the first candidate HVAC operating function is a heating function, a first heat pump heating call is applied to the HVAC system according to a first heat pump call convention, and the room temperature is monitored to sense an associated temperature change. If an associated temperature rise is detected, then a conclusion is made that the heat pump heating functionality has been successfully carried out and the HVAC system has the first heat pump call convention. In contrast, if an associated temperature decrease is detected upon applying the first heat pump heating call, a second heat pump heating call is applied to the HVAC system according to a second heat pump call convention, and the room temperature is again monitored to sense an associated temperature change. If an associated temperature rise is detected, then a conclusion is made that the heat pump heating functionality has been successfully carried out and the HVAC system has the second heat pump call convention, whereas an indication of an error condition is provided on the user display if the associated temperature rise is not detected. If the first candidate HVAC operating function is a cooling function, a first heat pump cooling call is applied to the HVAC system according to the first (or second) heat pump call convention, and the room temperature is monitored to sense an associated temperature change. If an associated temperature decrease is detected, then a conclusion is made that the heat pump cooling functionality has been successfully carried out and the HVAC system has the first (or second) heat pump call convention. In contrast, if an associated temperature rise is detected upon applying the first heat pump cooling call, a second heat pump cooling call is applied to the HVAC system according to the second (or first) heat pump call convention, and the room temperature is again monitored to sense an associated temperature change. If an associated temperature decrease is detected, then a conclusion is made that the heat pump cooling functionality has been successfully carried out and the HVAC system has the second (or first) heat pump call convention, whereas an indication of an error condition is provided on the user display if the associated temperature decrease is not detected. For one embodiment, the first heat pump call convention comprises (i) for a heat pump heating call, energizing a cooling call (Y1) signal type while not energizing the heat pump (O/B) signal type, and (ii) for a heat pump cooling call, energizing Y1 while also energizing O/B, while the second heat pump call convention is a reverse of the first convention, i.e., energizing Y1 while also energizing O/B for a heat pump heating call, and energizing Y1 while not energizing O/B for a heat pump cooling call. Advantageously, the identification of the heat pump call convention is made automatically in the background, without requiring the user to manually adjust any wirings or settings, and without requiring the user to tell the thermostat what particular actions the HVAC system is taking or not taking.